As I stated earlier, Morrison used it to highlight his chapter on the Mexican war in his Oxford History of the American People but he does not annotate it. I take it as an indication he thought it was from that era but I don't know. I always thought it was in spite of the myth about the term "gringo". A query, Was the song known in Ireland previous to the Mexican War? If so, it may well have been sung by American soldiers during the Mexican war. Keep in mind at that time the American Army was made up of a large percentage of foriegners. Most of them were Irish or German. But an answer to the lack of broadsides may be found in that the majority of the irish who immigrated worried first about making a living and then about getting their traditional music into print. Kindest regards, Neil